Question 2 A graduate student N was conducting a series of experiments on a new alloyed cylinder 12 mm in diameter and 9

[answerhappygod]

Question 2 A Graduate Student N Was Conducting A Series Of Experiments On A New Alloyed Cylinder 12 Mm In Diameter And 9 1 (85.64 KiB) Viewed 19 times

Question 2 A graduate student N was conducting a series of experiments on a new alloyed cylinder 12 mm in diameter and 94 mm long. The horizontal cylinder was being heated internally with a 45 W heater and is subjected to a cross flow of air in a wind tunnel. Under specific air velocity and temperature of 10 m/s and 26.2°C, respectively, the average cylinder surface temperature was measured to be 128.4°C. N estimated that 20% of the power supplied by the heater dissipates away. a) Determine the average convective heat transfer coefficient from N's experimental observations. b) Compare N's experimental result with the convection coefficient computed from an appropriate correlation. Determine the heat lost expected from the alloyed cylinder. (20 marks) c) Give reasons (at least 2) on why N's experimental result differs from that obtained from the selected correlation. Suggest a way to reduce the difference. (5 marks) (a)The average convective heat transfer coefficient from N's experimental observations. i) Sketch the problem (type of geometry) - no time to be Picasso here. ii) List your assumptions, you may add more later, the relevant ones must be listed iii) You will need the thermophysical properties of the fluid, at what temperature? Interpolate when differences between listed temperatures are significant. iv) You will not be needing any correlation here, do you? Power supplied was given but 20% is lost, what does that mean? (b) Compare N's experimental result with the convection coefficient computed from an appropriate correlation. Now you will need to select a correlation for Nu to determine h Then, using that h, determine the heat lost expected from the alloyed cylinder by forced convection. (c)Give reasons (at least 2) on why N's experimental result differs from that obtained from the selected correlation. Suggest a way to reduce the difference. Remember I stated in class about how correlations have been obtained?